Qualitative Assessment of Contact Behavior in Fretting Wear of Dissimilar Mating Pairs Using Frictional Dissipation Energy Density Approach

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Pankaj Dhaka ◽  
Raghu V. Prakash
Keyword(s):  
Finite Element ◽  
Energy Density ◽  
Material Properties ◽  
Dissimilar Materials ◽  
Fretting Wear ◽  
Experimental Methodology ◽  
Mating Pair ◽  
Dissipation Energy ◽  
Contact Behavior ◽  
Frictional Dissipation

Abstract Fretting is a damaging phenomenon, generally observed when a mating pair is subjected to a small amplitude of oscillatory motion. The contact behavior in fretting is governed by a complex interaction between mechanical properties of mating pair, contact geometry, and loading conditions. In most of the practical applications, dissimilar materials are chosen for a contacting pair with one of the materials having superior material properties than other so as to replace the worn-out or unfit component during the maintenance. In the literature, many researchers have studied the effect of dissimilar materials on fretting behavior but mainly in the context of hardness. As experimental methodology has been adopted in these studies, the effect of dissimilar material properties has been reported in terms of global variables like wear volume or fretting fatigue life, but its influence on underlying local contact tractions could not be studied. In the present work, a two-dimensional finite element analysis has been carried out for a cylinder-on-plate configuration. The effect of dissimilar materials for the mating pair has been studied by modeling elastic–plastic behavior for combinations of three different materials, namely, SS 304, ASTM A302-B, and aluminum. The validation of the finite element model is carried out by comparing the results of elastic analysis with the analytical solutions available in the literature. The pertinent contact parameters in the context of fretting wear, namely, contact pressure, contact slip, and contact stresses are extracted. A frictional dissipation energy density-based approach is used for the qualitative comparison of the fretting damage for different cases and validated with the literature data.

A Novel Three-Dimensional Finite Element Model to Simulate Third Body Effects on Fretting Wear of Hertzian Point Contact in Partial Slip

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Arman Ahmadi ◽  
Farshid Sadeghi
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Three Dimensional ◽  
Point Contact ◽  
Fretting Wear ◽  
Partial Slip ◽  
Wear Particles ◽  
Third Body ◽  
Stick Slip ◽  
The Third

Abstract In this investigation, a finite element (FE) model was developed to study the third body effects on the fretting wear of Hertzian contacts in the partial slip regime. An FE three-dimensional Hertzian point contact model operating in the presence of spherical third bodies was developed. Both first bodies and third bodies were modeled as elastic–plastic materials. The effect of the third body particles on contact stresses and stick-slip behavior was investigated. The influence of the number of third body particles and material properties including modulus of elasticity, hardening modulus, and yield strength were analyzed. Fretting loops in the presence and absence of wear particles were compared, and the relation between the number of cycles and the hardening process was evaluated. The results indicated that by increasing the number of particles in contact, more load was carried by the wear particles which affect the wear-rate of the material. In addition, due to the high plastic deformation of the debris, the wear particles deformed and took a platelet shape. Local stick-slip behavior over the third body particles was also observed. The results of having wear debris with different material properties than the first bodies indicated that harder wear particles have a higher contact pressure and lower slip at the location of particles which affects the wear-rate.

Solutions of the Right Classes for Laminated Composites Satisfying Interlamina Physics

2001 ◽  
Author(s):  
K. S. Surana ◽  
H. Ngyun
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Laminated Composites ◽  
Dissimilar Materials ◽  
Finite Element Formulation ◽  
Element Formulation ◽  
Computational Framework ◽  
Mixed Formulations ◽  
The Right ◽  
Mesh Refinements

Abstract This paper presents a new theoretical and computational framework for computing solutions of right classes for laminated composites using 2D p-version least squares finite element formulation incorporating the correct physics of interlamina behavior. At the interface between two laminas of dissimilar materials we have continuity of displacements u, v, stresses σyy, τxy, and strain εxx, while the stress σxx and the strains εyy and γxy are discontinuous. Thus, a finite element formulation, incorporating the physics of laminate behavior, would require interpolation of u, v, εxx, σyy and τxy instead of u, v, σxx, σyy and τxy which is generally the case in most mixed formulations. In the p-version LSFEF presented here, we interpolate u, v and σyy, τxy (εxx = ∂u/∂x is used to eliminate εxx as a variable) using appropriate p-version interpolations which would ensure correct interlamina behavior of these components. When the mating lamina properties are different, interlamina discontinuity of σxx, εyy and γxy is automatically generated due to dissimilar material properties of the laminas. In this formulation interlamina jumps in σxx, εyy and γxy do not constitute singularities, hence mesh refinements and higher p-levels are not needed in the vicinity of inter-lamina boundaries. The major thrust of this paper is to construct interpolations for the dependant variables that are of right classes in appropriate spaces so that a sequence of converged solutions in these spaces may be computed which, when converged, would yield a numerical solution that has exactly the same characteristics (in terms of continuity and differentiability) as the analytical or theoretical (strong) solution.

Bone Remodeling Algorithm Incorporating Various Quantities as Mechanical Stimulus and Assuming Initial Microcrack in Bone

2017 ◽  
Vol 754 ◽  
pp. 189-193
Author(s):  
Libor Borák ◽  
Petr Marcián
Keyword(s):  
Finite Element ◽  
Bone Resorption ◽  
Energy Density ◽  
Bone Remodeling ◽  
Material Properties ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Mechanical Stimulus ◽  
Coupled Processes ◽  
Bone Damage

It is widely accepted that bones have the ability to adapt to new biomechanical environment by changing their material properties, geometry and inner architecture. Bones have also an exceptional ability to self-repair, to remove microcracks and to prevent the bone damage caused by the fatigue failure. These abilities are enabled through coupled processes of bone resorption and bone formation, the processes collectively referred to as bone remodeling. Numerous studies have shown that bone remodeling is governed by combination of mechanical stimulus (strains) and its frequency, both sensed by sensor cells (osteocytes). Through mechanotransduction, the stimulus is transmitted to actor cells (osteoclasts, osteoblasts) that actually do the bone resorption or formation. Several theories have been proposed to predict bone remodeling and several finite-element-based algorithms have been introduced. The vast majority of them uses strain energy density as the mechanical stimulus. The purpose of this paper is to investigate and discuss the applicability of also other strain-based representations of the mechanical stimulus in simulations of remodeling of bone with an initial microcrack. The need for developing more reliable models is essential for both clinicians and engineers who are interested, for instance, in prediction of bone performance when various implants are involved.

scholarly journals Finite Element Modelling and Simulating Effects of Hairiness Performance on Hairiness Entanglement During Fabric Pilling

2021 ◽  
Author(s):  
Qi Xiao ◽  
Rui Wang ◽  
Hongyu Sun ◽  
Jingru Wang
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Strain Energy ◽  
Dissipation Energy ◽  
Motion Equations ◽  
Dynamic Motion ◽  
Element Simulation ◽  
Frictional Dissipation ◽  
Simulation Results ◽  
Good Agreement

Abstract For analyzing behaviors of hairiness entanglement during fabric pilling, nonlinear dynamic motion equations are deduced based on the elastic thin rod element, combined with the moving characteristics of hairiness, which follow the principles of mechanical equilibrium and energy conservation. The finite element simulation model of the effects of hairiness performance on behaviors of hairiness entanglement was established by ABAQUS. The analysis solution values of nonlinear dynamics were compared with the finite element simulation results. The results showed that hairiness elastic modulus, hairiness friction coefficient and hairiness diameter have significant effects on frictional dissipation energy, strain energy and kinetic energy produced by hairiness entanglement during pilling. Compared the finite element simulation results with analysis solution values, they are in good agreement. The fitness is greater than 0.96, which verifies the validity of finite element method.

A Critical Investigation on the Nature of Material Dependency of Elastic-Plastic Contact Behavior

2007 ◽  
Author(s):  
R. Malayalamurthi ◽  
R. Marappan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Material Properties ◽  
Elastic Limit ◽  
Plastic State ◽  
Finite Element Method Analysis ◽  
Contact Behavior ◽  
Elastic Plastic ◽  
Method Analysis ◽  
Critical Investigation

This work attempts to make an investigation on the nature of material dependency of elastic-plastic contact behavior through a more accurate contact analysis between a deformable sphere and a rigid flat by finite element method. Analysis is carried out beyond elastic limit, till the inception of plasticity for various materials with different radii. It is found those materials with Young’s modulus to yield stress (E/Y) ratio less than 300 show strikingly different contact phenomena. Equation for hardness in terms of E/Y ratio for these materials is presented. A proposal for fixing the point of attaining fully plastic state is suggested. Existing disagreement over the dependency of hardness on material properties is critically examined.

Determination of Charge Coefficient of Piezoelectric Films Using a Combined Finite Element Model and Dynamic Loading Technique

2020 ◽  
Vol 835 ◽  
pp. 229-242
Author(s):  
Oboso P. Bernard ◽  
Nagih M. Shaalan ◽  
Mohab Hossam ◽  
Mohsen A. Hassan
Keyword(s):  
Finite Element ◽  
Dynamic Loading ◽  
Material Properties ◽  
Accurate Determination ◽  
Substrate Material ◽  
Experimental Results ◽  
Piezoelectric Composite ◽  
Piezoelectric Film ◽  
Piezoelectric Charge

Accurate determination of piezoelectric properties such as piezoelectric charge coefficients (d33) is an essential step in the design process of sensors and actuators using piezoelectric effect. In this study, a cost-effective and accurate method based on dynamic loading technique was proposed to determine the piezoelectric charge coefficient d33. Finite element analysis (FEA) model was developed in order to estimate d33 and validate the obtained values with experimental results. The experiment was conducted on a piezoelectric disc with a known d33 value. The effect of measuring boundary conditions, substrate material properties and specimen geometry on measured d33 value were conducted. The experimental results reveal that the determined d33 coefficient by this technique is accurate as it falls within the manufactures tolerance specifications of PZT-5A piezoelectric film d33. Further, obtained simulation results on fibre reinforced and particle reinforced piezoelectric composite were found to be similar to those that have been obtained using more advanced techniques. FE-results showed that the measured d33 coefficients depend on measuring boundary condition, piezoelectric film thickness, and substrate material properties. This method was proved to be suitable for determination of d33 coefficient effectively for piezoelectric samples of any arbitrary geometry without compromising on the accuracy of measured d33.

scholarly journals Downscaled Finite Element Modeling of Metal Targets for Surface Roughness Level under Pulsed Laser Irradiation

2021 ◽  
Vol 11 (3) ◽  
pp. 1253
Author(s):  
Evaggelos Kaselouris ◽  
Kyriaki Kosma ◽  
Yannis Orphanos ◽  
Alexandros Skoulakis ◽  
Ioannis Fitilis ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Finite Element ◽  
Surface Acoustic Waves ◽  
Pulsed Laser ◽  
Multiscale Simulation ◽  
Experimental Methodology ◽  
Computational Domain ◽  
Area Of Interest ◽  
Depth Analysis ◽  
Laser Solid Interactions

A three-dimensional, thermal-structural finite element model, originally developed for the study of laser–solid interactions and the generation and propagation of surface acoustic waves in the macroscopic level, was downscaled for the investigation of the surface roughness influence on pulsed laser–solid interactions. The dimensions of the computational domain were reduced to include the laser-heated area of interest. The initially flat surface was progressively downscaled to model the spatial roughness profile characteristics with increasing geometrical accuracy. Since we focused on the plastic and melting regimes, where structural changes occur in the submicrometer scale, the proposed downscaling approach allowed for their accurate positioning. Additionally, the multiscale simulation results were discussed in relation to experimental findings based on white light interferometry. The combination of this multiscale modeling approach with the experimental methodology presented in this study provides a multilevel scientific tool for an in-depth analysis of the influence of heat parameters on the surface roughness of solid materials and can be further extended to various laser–solid interaction applications.

A semianalytical and finite-element solution to the unbonded contact between a frictionless layer and an FGM-coated half-plane

2017 ◽  
Vol 24 (2) ◽  
pp. 448-464 ◽  
Author(s):  
Jie Yan ◽  
Changwen Mi ◽  
Zhixin Liu
Keyword(s):  
Integral Equation ◽  
Finite Element ◽  
Singular Integral Equation ◽  
Contact Problem ◽  
Singular Integral ◽  
Material Properties ◽  
Elastic Layer ◽  
Coated Substrate ◽  
Receding Contact ◽  
Contact Size

In this work, we examine the receding contact between a homogeneous elastic layer and a half-plane substrate reinforced by a functionally graded coating. The material properties of the coating are allowed to vary exponentially along its thickness. A distributed traction load applied over a finite segment of the layer surface presses the layer and the coated substrate against each other. It is further assumed that the receding contact between the layer and the coated substrate is frictionless. In the absence of body forces, Fourier integral transforms are used to convert the governing equations and boundary conditions of the plane receding contact problem into a singular integral equation with the contact pressure and contact size as unknowns. Gauss–Chebyshev quadrature is subsequently employed to discretize both the singular integral equation and the force equilibrium condition at the contact interface. An iterative algorithm based on the method of steepest descent has been proposed to numerically solve the system of algebraic equations, which is linear for the contact pressure but nonlinear for the contact size. Extensive case studies are performed with respect to the coating inhomogeneity parameter, geometric parameters, material properties, and the extent of the indentation load. As a result of the indentation, the elastic layer remains in contact with the coated substrate over only a finite interval. Exterior to this region, the layer and the coated substrate lose contact. Nonetheless, the receding contact size is always larger than that of the indentation traction. To validate the theoretical solution, we have also developed a finite-element model to solve the same receding contact problem. Numerical results of finite-element modeling and theoretical development are compared in detail for a number of parametric studies and are found to agree very well with each other.

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